crypto_client: set session ID for RPCs (#953)
crypto_client: set session ID for RPCs (#953)

Apparently this is a requirement when you are sending multiple RPCs
that might result in UI routing, so the service doesn't get confused
about which RPC to respond to after GUI interaction.

Issue: keybase/client#2637
keybase/client,keybase/client,keybase/client,keybase/client,keybase/kbfs,keybase/client,keybase/kbfs,keybase/kbfs,keybase/kbfs,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client,keybase/client